There are four global issues of concern that are addressed by the current invention;    i) The diminishing capacity of the world production of mineral oil;    ii) The effect of the increasing carbon dioxide emission on global warming;    iii) The contribution from combustion of sulfur-containing fuel to acidification of rainwater;    iv) The effective and economic utilization of available renewable energy sources may not be suitable for conventional applications.
Current evaluation of the world oil production predicts the production to peak around the year 2010. As the world production capacity is believed to behave like a bell curve the expectations are that we will have diminishing production capacity within a few decades from now. Demand on the other hand rises rapidly and it has become foreseeable that in fairly short time, gasoline production will not meet demand.
It is therefore very important to develop processes that allow utilization of alternative energy sources to provide fuel that can immediately substitute the currently used gasoline and diesel distilled from petroleum oil. Such fuel which is compatible with combustion engines as they are today will render the need for major, time consuming, technical developments and infrastructural changes unnecessary.
Currently, two processes have been used on industrial scale to produce synthetic liquid hydrocarbon fuel. One is the SASOL process which is based on classic Fisher-Tropsch chemistry and converts coal to syngas, which is converted to a variety of hydrocarbons via the Fisher-Tropsch synthesis. The other is the Mobil Methanol-to-Gasoline process (MTG), which was utilized on large scale in New Zealand to convert natural gas to high octane gasoline fuel.
Syngas or synthesis gas is a term used for gases of varying composition that are generated in coal gasification, steam reforming of natural gas and some types of waste-to-energy facilities. The name comes from their use in creating synthetic petroleum for use as a fuel or lubricant via Fischer-Tropsch synthesis. Syngas consists primarily of carbon monoxide and hydrogen, and can be produced from natural gas through steam reforming: CH4+H2O→CO+3H2,
partial oxidation: CH4+½ O2→CO+2H2,
or combination of both.
The Fisher Tropsch process was developed by the German researchers Franz Fisher and Hans Tropsch in the 1920s. It is a well documented process that has been used on industrial scale for production of diesel and other synthetic petroleum products for decades. This process is used by a number of companies today to produced low-sulfur diesel and other petroleum products on large scale. For example, SASOL has implemented this process since 1955 to produce petroleum fuel, AMSOIL introduced their first synthetic diesel in 1975 and since 1993 shell operates a 14700 bbl/day GTL plant in Malaysia.
The conversion of syngas, obtained from natural gas, to methanol is a very well documented process. The process has been run on industrial scale for decades and the world production of methanol from natural gas is now around 30 MMtpa (million metric tones per annum).
The conversion of methanol to gasoline using the Mobile methanol to gasoline process (MTG) is a viable alternative to the Fisher-Tropsch synthesis when converting syngas to liquid fuel. This process, where the syngas is first converted to methanol and the methanol is converted in a second step, over dimethyl ether (DME) to high octane gasoline, went first on stream in New Zealand in 1985 and was producing about 14,500 B/D a year later. Since 1997 the New Zealand facilities are used exclusively for methanol production.
The global carbon dioxide emission has grown enormously in the past 50 years. In 1950 the global emission was about 1000 million tons carbon equivalent, but has now reached close to 10,000 million tons carbon equivalent. About one fourth of this is industrial emission. As a consequence thereof, the concentration of carbon dioxide in the atmosphere is generally estimated to have increased about 30% from pre-industrial times. Due to the greenhouse effect of carbon dioxide, this enormous emission and increased levels cause increasing concern about the consequences of global warming.
It is therefore an important challenge to develop a process that allows recycling carbon dioxide to a valuable product such as liquid fuel. It is even more beneficial to develop a process to recycle carbon dioxide to a liquid fuel that is equivalent or even superior to the currently used gasoline and diesel, and can substitute these without any need for technical or infrastructural changes.
To date, commercially viable solutions have not been provided for producing liquid fuels from carbon dioxide and water. The present invention seeks to address this problem by a novel combination of several processes for conversion of electrical energy to chemical energy in the form of synthetic liquid hydrocarbon fuels that can readily replace conventional liquid fuels from natural oil reserves.